Plant essential oil mosquito-repellent slow-release gel and preparation method thereof

Abstract

The invention discloses plant essential oil mosquito-repelling slow-release gel and a preparation method thereof, and belongs to the field of mosquito-repelling materials. The plant essential oil mosquito-repelling slow-release gel disclosed by the invention is prepared from the following raw material components: plant essential oil microcapsules, modified graphene oxide, hydroxybutyl chitosan and hyaluronic acid, wherein the plant essential oil microcapsules are obtained by wrapping compound plant essential oil with gelatin and Arabic gum as shell materials; the modified graphene oxide is obtained by modifying graphene oxide with dopamine; wherein the compound plant essential oil is prepared from the following components in parts by weight: 20 to 30 parts of peppermint oil, 15 to 25 parts of litsea cubeba oil, 15 to 25 parts of cananga odorata oil, 10 to 20 parts of bay oil and 15 to 25 parts of ginger oil; the plant essential oil mosquito-repelling slow-release gel prepared by the invention has the advantages of better slow-release effect, better mosquito-repelling effect, higher mechanical strength and soothing smell.

Description

Technical Field

[0001] The invention relates to a plant essential oil mosquito repellent slow-release gel and a preparation method thereof. Background Art

[0002] Mosquitoes and flies not only interfere with the normal life and work of humans and animals, but may also spread a variety of diseases, posing a threat to public health. Most of the existing mosquito and fly repellent or killing products on the market are based on chemical synthetic materials. Although they can effectively reduce the number of mosquitoes and flies in the short term, these products often contain certain toxicity and need to strictly follow safety guidelines when used. In particular, long-term use may have adverse effects on the environment and the health of humans and animals.

[0003] At present, mosquito repellent products on the market can be roughly divided into two categories: one is physical methods, such as fly killer lamps, mosquito killer lamps and other equipment, which attract mosquitoes and flies to specific locations to capture or eliminate them. Since these products need to be fixed and installed, and their mechanism of action is relatively passive, they are more common in indoor environments, and their effectiveness is limited for people who engage in outdoor activities. The second is chemical methods, namely various sanitary insecticides. These products can disinfect mosquitoes and flies in the environment on a large scale, thereby reducing the density of mosquitoes and flies in local areas. However, for mosquitoes and flies that directly contact humans and animals and cause harassment and bites, the effect of chemical insecticides is not ideal, and they are more of a symptomatic treatment rather than a fundamental solution.

[0004] In addition, chemical sanitation pesticides have a certain residual time, which poses additional safety challenges in industries such as food processing. Residual substances may contaminate the food chain and affect human health. At the same time, the long-term use of chemical ingredients will not only aggravate environmental pollution, but may also cause mosquitoes and flies to develop resistance, further increasing the difficulty of control.

[0005] In view of the above problems, it is particularly urgent to develop a new type of mosquito repellent product that is safe, effective, and has no toxic side effects. The present invention proposes a mosquito repellent slow-release gel using plant essential oil as an active ingredient, which aims to overcome the problems of poor mosquito repellent effect, poor odor, insufficient gel adhesion and mechanical properties of existing products. By using natural plant essential oils, not only can a good mosquito repellent effect be achieved, but also the safety of the product can be ensured, avoiding negative impacts on the environment and human health. At the same time, by optimizing the gel formula, the adhesion and mechanical properties of the product are improved, making it more suitable for long-term use requirements in different scenarios. Summary of the invention

[0006] The purpose of the present invention is to provide a plant essential oil mosquito repellent slow-release gel and a preparation method thereof, so as to solve the technical problems mentioned in the above background technology.

[0007] The technical solution for achieving the purpose of the present invention is:

[0008] A plant essential oil mosquito repellent slow-release gel, the raw material components of which include plant essential oil microcapsules, modified graphene oxide, hydroxybutyl chitosan and hyaluronic acid.

[0009] Furthermore, the plant essential oil microcapsules are obtained by encapsulating the compound plant essential oil with gelatin and gum arabic as shell materials.

[0010] Gelatin and gum arabic powder have good biodegradability and biocompatibility, good emulsification ability, excellent film-forming performance, good retention ability for aroma substances, and are widely available and inexpensive. Using gelatin and gum arabic powder to encapsulate compound plant essential oils can effectively improve the utilization rate and stability of the compound plant essential oils and delay the release of the odor of the compound plant essential oils.

[0011] Furthermore, the compound plant essential oil comprises the following components by weight: 20 to 30 parts by weight of peppermint oil, 15 to 25 parts by weight of litsea cubeba oil, 15 to 25 parts by weight of ylang-ylang oil, 10 to 20 parts by weight of laurel oil, and 15 to 25 parts by weight of ginger oil.

[0012] Mint is an important medicinal and edible plant. The young and tender stem tips can be used as vegetables, and the whole plant can be used as medicine. It has the effects of dispersing wind-heat, clearing the head, relieving sore throat, promoting rashes, and soothing the liver and promoting qi. It is used to treat wind-heat colds, the initial onset of wind-heat, headaches, red eyes, throat paralysis, mouth sores, rubella, measles, chest and flank distension and other symptoms. The cooling sensation and sedative effect of peppermint oil help improve sleep quality, especially when used at night. Peppermint oil contains volatile compounds such as menthol, limonene, and eucalyptol, which can repel mosquitoes to a certain extent.

[0013] Litsea cubeba oil is rich in monoterpene compounds, such as α-pinene and β-pinene. These compounds have strong volatility and spicy aroma, which can effectively repel mosquitoes and flies. Litsea cubeba oil can warm the body and relieve fatigue. At the same time, its spicy aroma helps dispel negative emotions, help relax the body and mind, relieve fatigue, and improve emotional stability.

[0014] Ylang ylang oil contains a variety of volatile compounds, such as phenylethanol and linalool, which have a strong aroma and can effectively repel insects, including mosquitoes and flies. In medicine, ylang ylang oil is widely used to calm nerves, relieve anxiety and tension, help deep relaxation and improve sleep quality. At the same time, its unique floral scent can increase the layering of the aroma and enhance the overall comfort.

[0015] Bay oil contains a variety of volatile compounds, such as carvacrol and eugenol, which have a strong aroma and can effectively repel insects, including mosquitoes and flies. In medicine, bay oil is widely used to soothe and relax, relieve muscle pain and fatigue, and its warm woody aroma helps balance emotions, reduce anxiety and tension, and promote deep relaxation and good sleep quality.

[0016] Ginger oil is rich in active ingredients such as gingerol and shogaol, which give it a unique warm, spicy aroma. The strong smell of ginger oil can effectively repel insects, including mosquitoes and flies; in medicine, ginger oil is widely used to relieve muscle pain and arthritis symptoms, promote blood circulation, and reduce fatigue. Its warm aroma also has a soothing and relaxing effect, helping to balance emotions, reduce anxiety and tension, and enhance overall comfort.

[0017] The plant essential oils in the above formula, among which the cool feeling of peppermint oil is combined with the warm feeling of wild pepper oil, form a balanced aroma basis; the floral fragrance of ylang-ylang oil and the woody fragrance of laurel oil and ginger oil increase the layering of the aroma, making the overall aroma richer and more harmonious; it helps to relax the body and mind, relieve a day's fatigue, and at the same time achieve a better mosquito repellent effect.

[0018] Furthermore, the modified graphene oxide is obtained by modifying graphene oxide with dopamine.

[0019] The present invention also provides a method for preparing a plant essential oil mosquito repellent slow-release gel, comprising the following steps:

[0020] (1) 0.2-0.6 parts by weight of plant essential oil microcapsules are mixed with 2 parts by weight of PBS buffer, stirred until uniformly dispersed, then 0.1-0.3 parts by weight of hydroxybutyl chitosan is added and stirred until the hydroxybutyl chitosan is dissolved, and then 0.003-0.005 parts by weight of modified graphene oxide is added and stirred and dispersed at 0-4° C. for 25-35 minutes to obtain a modified graphene oxide / hydroxybutyl chitosan mixed solution;

[0021] (2) At 0-4° C., the modified graphene oxide / hydroxybutyl chitosan mixed solution and the hyaluronic acid solution are mixed in a volume ratio of 1.5-2.5:1 to obtain a plant essential oil mosquito repellent sustained-release gel.

[0022] Furthermore, the preparation steps of the plant essential oil microcapsules are as follows: gelatin and water are mixed at a mass ratio of 1.5-2.5:97.5-98.5 at 50°C to obtain a gelatin solution; gum arabic powder and water are mixed at a mass ratio of 1.5-2.5:97.5-98.5 at 50°C to obtain a gum arabic solution; the gelatin solution and the gum arabic solution are mixed in equal volumes to obtain a mixed solution; the compound plant essential oil and the mixed solution are then emulsified at a mass ratio of 2:1 using an emulsifying homogenizer at high speed for 2.5-3.5 minutes, followed by stirring and mixing at 39-41°C and 400-800rpm, adjusting the pH to 3.4-4.0 with a 10% acetic acid solution, followed by stirring and reacting for 30 minutes, then cooling to below 10°C, adjusting the pH to 6 with a 10% sodium bicarbonate solution, adding 0.5-0.7 parts by mass of transglutaminase, and then performing a curing reaction for 5-7 hours, followed by filtering, washing, centrifuging, and drying to obtain plant essential oil microcapsules.

[0023] Furthermore, the pH of the PBS buffer is 7.4.

[0024] Furthermore, the preparation steps of the modified graphene oxide are as follows: 0.03 to 0.05 parts by mass of graphene oxide are dispersed in 30 to 50 parts by mass of 100 mM tris(hydroxymethyl)aminomethane hydrochloride buffer and ultrasonicated for 20 to 40 minutes, then 0.03 to 0.05 parts by mass of dopamine are added, and ultrasonication is continued for 20 to 40 minutes. After the ultrasonication, stirring is performed for 23 to 25 hours, and the supernatant is discarded by centrifugation. The obtained precipitate is repeatedly washed with ethanol and water for 6 to 8 times, and the modified graphene oxide is obtained after freeze-drying.

[0025] Furthermore, the preparation step of the hyaluronic acid solution is as follows: 0.09 to 0.11 parts by mass of hyaluronic acid is dissolved in a PBS buffer solution with a pH of 7.4 to obtain a 100 mg / mL hyaluronic acid solution.

[0026] By adopting the above technical solution, the present invention has the following beneficial effects:

[0027] (1) The plant essential oil mosquito repellent slow-release gel of the present invention comprises plant essential oil microcapsules, modified graphene oxide, hydroxybutyl chitosan and hyaluronic acid; wherein the plant essential oil microcapsules are obtained by encapsulating compound plant essential oil with gelatin and gum arabic as shell materials; the modified graphene oxide is obtained by modifying graphene oxide with dopamine; wherein the plant essential oil microcapsules use gelatin and gum arabic as shell materials to encapsulate the compound plant essential oil, thereby ensuring that the effective ingredients of the essential oil can be slowly released and prolonging the mosquito repellent time, and avoiding the irritation or discomfort that may be caused by direct contact of the essential oil with the skin; the modified graphene oxide is obtained by Dopamine modification improves the agglomeration problem of graphene oxide and enhances the dispersibility of graphene oxide in the gel material, thereby enhancing the biocompatibility and mechanical strength of the plant essential oil mosquito repellent sustained-release gel, making the gel more stable and durable; the addition of hydroxybutyl chitosan and hyaluronic acid further enhances the moisturizing properties and skin affinity of the gel, making the product more comfortable and easy to apply, while also enhancing the adhesion and film-forming properties of the gel, ensuring long-term effective protection; the plant essential oil mosquito repellent sustained-release gel is not only safe and environmentally friendly, but also has the characteristics of long-lasting and mildness, and is suitable for mosquito repellent needs in a variety of occasions.

[0028] (2) The compound plant essential oil of the present invention comprises the following components by weight: 20 to 30 parts by weight of peppermint oil, 15 to 25 parts by weight of Litsea cubeba oil, 15 to 25 parts by weight of ylang-ylang oil, 10 to 20 parts by weight of laurel oil, and 15 to 25 parts by weight of ginger oil. The plant essential oils of the above formula are used, wherein the cooling sensation of the peppermint oil is combined with the warm sensation of the Litsea cubeba oil to form a balanced aroma basis; the floral fragrance of the ylang-ylang oil and the woody fragrance of the laurel oil and the ginger oil increase the layering of the aroma, making the overall aroma richer and more harmonious; it helps to relax the body and mind, relieve a day's fatigue, and at the same time achieve a better mosquito repellent effect.

[0029] (3) The plant essential oil mosquito repellent sustained-release gel of the present invention adopts hydroxybutyl chitosan, which is a product obtained by conjugating hydrophilic hydroxybutyl groups to the amino and hydroxyl structures of chitosan. Hydroxybutyl chitosan not only retains the good chemical properties of chitosan, but also significantly improves its solubility and imparts reversible temperature response characteristics. In the temperature range of 4 to 50°C, hydroxybutyl chitosan exhibits excellent temperature sensitivity: at low temperatures, it is in a transparent sol state with good fluidity, and as the temperature rises to the gel point temperature, it quickly transforms into a flexible white semi-solid gel state. This characteristic makes the gel easy to disperse when applied, and quickly forms a stable protective layer on the skin surface, effectively prolonging the sustained-release time of the plant essential oil.

[0030] (4) The plant essential oil mosquito repellent sustained-release gel of the present invention also introduces plant essential oil microcapsules, dopamine-modified graphene oxide and hyaluronic acid. The amino groups on the dopamine-modified graphene oxide react with the aldehyde groups in the hyaluronic acid to cross-link and are interspersed in the hydroxybutyl chitosan gel network. This cross-linking process significantly increases the cross-linking density of the gel, forming a stable three-dimensional network structure; the mechanical strength and stability of the gel are improved, making it more durable and less prone to rupture, and its antibacterial properties are also enhanced, ensuring the long-lasting mosquito repellent effect and safety of the product. DETAILED DESCRIPTION

[0031] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with specific implementation methods.

[0032] Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without making any creative work shall fall within the scope of protection of the present invention.

[0033] The following embodiments are only used to more clearly illustrate the technical solutions of the present invention, and are not intended to limit the protection scope of the present invention.

[0034] Example 1

[0035] A method for preparing a plant essential oil mosquito repellent slow-release gel comprises the following steps:

[0036] 0.09 parts by mass of hyaluronic acid was dissolved in a PBS buffer solution having a pH of 7.4 to obtain a 100 mg / mL hyaluronic acid solution; 0.2 parts by mass of plant essential oil microcapsules were mixed with 2 parts by mass of a PBS buffer solution having a pH of 7.4, and stirred until uniformly dispersed, and then 0.1 parts by mass of hydroxybutyl chitosan was added and continued to be stirred until the hydroxybutyl chitosan was dissolved, and then 0.003 parts by mass of modified graphene oxide was added and stirred and dispersed at 1000 rpm at 0°C for 25 minutes to obtain a modified graphene oxide / hydroxybutyl chitosan mixed solution; at 0 to 4°C, the modified graphene oxide / hydroxybutyl chitosan mixed solution was mixed with the hyaluronic acid solution in a volume ratio of 1.5:1 to obtain a plant essential oil mosquito repellent sustained-release gel;

[0037] The preparation method of modified graphene oxide is as follows: 0.03 parts by mass of graphene oxide is dispersed in 30 parts by mass of 100 mM tris(hydroxymethyl)aminomethane hydrochloride buffer and ultrasonicated for 20 minutes, then 0.03 parts by mass of dopamine is added, and ultrasonication is continued for 20 minutes. After the ultrasonication ends, stirring is performed for 23 hours, and the supernatant is discarded by centrifugation. The obtained precipitate is repeatedly washed with ethanol and water for 6 times, and the modified graphene oxide is obtained after freeze-drying.

[0038] The preparation steps of plant essential oil microcapsules are as follows: gelatin and water are mixed at a mass ratio of 1.5:98.5 at 50°C to obtain a gelatin solution; gum arabic powder and water are mixed at a mass ratio of 1.5:98.5 at 50°C to obtain a gum arabic solution; the gelatin solution and the gum arabic solution are mixed in equal volumes to obtain a mixed solution; then the compound plant essential oil and the mixed solution are emulsified at a mass ratio of 2:1 using an emulsifying homogenizer at high speed for 2.5 minutes, then stirred and mixed at 39°C and 400rpm, the pH is adjusted to 3.4 with a 10% acetic acid solution, then stirred and reacted for 30 minutes, then cooled to below 10°C, the pH is adjusted to 6 with a 10% sodium bicarbonate solution, 0.5 parts by mass of transglutaminase is added and a curing reaction is carried out for 5 hours, then filtered, washed, centrifuged and dried to obtain plant essential oil microcapsules.

[0039] The compound plant essential oil is prepared by compounding 20 parts by weight of peppermint oil, 25 parts by weight of litsea cubeba oil, 15 parts by weight of ylang-ylang oil, 20 parts by weight of laurel oil and 20 parts by weight of ginger oil.

[0040] Example 2

[0041] A method for preparing a plant essential oil mosquito repellent slow-release gel comprises the following steps:

[0042] 0.1 parts by mass of hyaluronic acid was dissolved in a PBS buffer solution having a pH of 7.4 to obtain a 100 mg / mL hyaluronic acid solution; 0.4 parts by mass of plant essential oil microcapsules were mixed with 2 parts by mass of a PBS buffer solution having a pH of 7.4, and stirred until uniformly dispersed, and then 0.2 parts by mass of hydroxybutyl chitosan was added and continued to be stirred until the hydroxybutyl chitosan was dissolved, and then 0.004 parts by mass of modified graphene oxide was added and stirred and dispersed at 1500 rpm for 30 minutes at 2°C to obtain a modified graphene oxide / hydroxybutyl chitosan mixed solution; at 2°C, the modified graphene oxide / hydroxybutyl chitosan mixed solution was mixed with the hyaluronic acid solution in a volume ratio of 2:1 to obtain a plant essential oil mosquito repellent sustained-release gel;

[0043] The preparation method of modified graphene oxide is as follows: 0.04 parts by mass of graphene oxide is dispersed in 40 parts by mass of 100 mM tris(hydroxymethyl)aminomethane hydrochloride buffer and ultrasonicated for 30 minutes, then 0.04 parts by mass of dopamine is added, and ultrasonication is continued for 30 minutes. After the ultrasonication ends, stirring is performed for 24 hours, and the supernatant is discarded by centrifugation. The obtained precipitate is repeatedly washed with ethanol and water for 7 times, and the modified graphene oxide is obtained after freeze-drying.

[0044] The preparation steps of plant essential oil microcapsules are as follows: gelatin and water are mixed at a mass ratio of 2:98 at 50°C to obtain a gelatin solution; gum arabic powder and water are mixed at a mass ratio of 2:98 at 50°C to obtain a gum arabic solution; the gelatin solution and the gum arabic solution are mixed in equal volumes to obtain a mixed solution; then the compound plant essential oil and the mixed solution are emulsified at a mass ratio of 2:1 using an emulsifying homogenizer at high speed for 3 minutes, then stirred and mixed at 40°C and 600rpm, the pH is adjusted to 3.7 with a 10% acetic acid solution, then stirred and reacted for 30 minutes, then cooled to below 10°C, the pH is adjusted to 6 with a 10% sodium bicarbonate solution, 0.6 parts by mass of transglutaminase is added and a curing reaction is carried out for 6 hours, then filtered, washed, centrifuged and dried to obtain plant essential oil microcapsules.

[0045] The compound plant essential oil is prepared by compounding 25 parts by weight of peppermint oil, 20 parts by weight of litsea cubeba oil, 20 parts by weight of ylang-ylang oil, 15 parts by weight of laurel oil and 20 parts by weight of ginger oil.

[0046] Example 3

[0047] A method for preparing a plant essential oil mosquito repellent slow-release gel comprises the following steps:

[0048] 0.11 parts by mass of hyaluronic acid was dissolved in a PBS buffer solution having a pH of 7.4 to obtain a 100 mg / mL hyaluronic acid solution; 0.6 parts by mass of plant essential oil microcapsules were mixed with 2 parts by mass of a PBS buffer solution having a pH of 7.4, and stirred until uniformly dispersed, and then 0.3 parts by mass of hydroxybutyl chitosan was added and continued to be stirred until the hydroxybutyl chitosan was dissolved, and then 0.005 parts by mass of modified graphene oxide was added and stirred and dispersed at 2000 rpm at 4°C for 35 minutes to obtain a modified graphene oxide / hydroxybutyl chitosan mixed solution; at 4°C, the modified graphene oxide / hydroxybutyl chitosan mixed solution was mixed with the hyaluronic acid solution at a volume ratio of 2.5:1 to obtain a plant essential oil mosquito repellent sustained-release gel;

[0049] The preparation method of modified graphene oxide is as follows: 0.05 parts by mass of graphene oxide is dispersed in 50 parts by mass of 100 mM tris(hydroxymethyl)aminomethane hydrochloride) buffer and ultrasonicated for 40 minutes, then 0.05 parts by mass of dopamine is added, and ultrasonication is continued for 40 minutes. After the ultrasonication ends, stirring is performed for 25 hours, and the supernatant is discarded by centrifugation. The obtained precipitate is repeatedly washed with ethanol and water for 6 to 8 times, and the modified graphene oxide is obtained after freeze-drying.

[0050] The preparation steps of plant essential oil microcapsules are as follows: gelatin and water are mixed at a mass ratio of 2.5:97.5 at 50°C to obtain a gelatin solution; gum arabic powder and water are mixed at a mass ratio of 2.5:97.5 at 50°C to obtain a gum arabic solution; the gelatin solution and the gum arabic solution are mixed in equal volumes to obtain a mixed solution; then the compound plant essential oil and the mixed solution are emulsified at a mass ratio of 2:1 using an emulsifying homogenizer at high speed for 3.5 minutes, then stirred and mixed at 41°C and 800rpm, the pH is adjusted to 4.0 with a 10% acetic acid solution, then stirred and reacted for 30 minutes, then cooled to below 10°C, the pH is adjusted to 6 with a 10% sodium bicarbonate solution, 0.7 parts by mass of transglutaminase is added and a curing reaction is carried out for 7 hours, then filtered, washed, centrifuged and dried to obtain plant essential oil microcapsules.

[0051] The compound plant essential oil is prepared by compounding 30 parts by weight of peppermint oil, 15 parts by weight of litsea cubeba oil, 20 parts by weight of ylang-ylang oil, 10 parts by weight of laurel oil and 25 parts by weight of ginger oil.

[0052] Example 4

[0053] The difference between Example 4 and Example 2 is only the composition of the compound plant essential oil; the compound plant essential oil of Example 4 is obtained by compounding 25 parts by mass of peppermint oil, 25 parts by mass of litsea cubeba oil, 25 parts by mass of ylang-ylang oil, 10 parts by mass of laurel oil, and 15 parts by mass of ginger oil; the remaining components and steps are the same as those in Example 2.

[0054] Comparative Example 1

[0055] The difference between Comparative Example 1 and Example 2 is that the raw material components of the plant essential oil mosquito repellent sustained-release gel include plant essential oil microcapsules, graphene oxide, hydroxybutyl chitosan, and hyaluronic acid; the remaining components and steps are the same as those in Example 2.

[0056] Comparative Example 2

[0057] The difference between Comparative Example 2 and Example 2 is that the raw material components of the plant essential oil mosquito repellent sustained-release gel include plant essential oil microcapsules, modified graphene oxide, chitosan, and hyaluronic acid; the remaining components and steps are the same as those in Example 2.

[0058] Comparative Example 3

[0059] The difference between Comparative Example 3 and Example 2 is that the raw material components of the plant essential oil mosquito repellent sustained-release gel include plant essential oil microcapsules, graphene oxide, chitosan, and hyaluronic acid; the remaining components and steps are the same as those in Example 2.

[0060] Comparative Examples 4 to 8

[0061] The difference between Comparative Examples 4 to 8 and Example 2 is that the compound plant essential oils in Comparative Examples 4 to 8 are pure peppermint oil, pure Litsea cubeba oil, pure Ylang-ylang oil, pure laurel oil, and pure ginger oil, respectively; the remaining components and steps are the same as those in Example 2.

[0062] Effect example

[0063] Repellency rate: 300 test insects are placed in a mosquito cage, and the test personnel expose a 40mm×40mm skin area on the back of their hands, with the rest of the hands tightly covered. The test personnel extend their arms into the mosquito cage for 2 minutes, and observe that mosquitoes land. Before their mouthparts pierce the skin, they shake their arms to drive them away, which is recorded as one test insect landing. If more than 30 test insects land, the test personnel and test insects have qualified attack power, and this person and the mosquitoes in this cage can be tested for repellency. Select 4 or more test personnel with qualified attack power (half male and half female, and they should not drink alcohol, tea or coffee before and during the test, and should not use products containing fragrances). Draw a 50mm×50mm skin area on the back of each hand, and press 1.5μL / cm on one hand. 2 The repellent to be tested is evenly applied with a dose of 1000 mg / kg, exposing 14 skin areas of 40 mm × 40 mm, and the rest of the hand is tightly covered. The other hand is used as a blank control. 2 hours after the repellent is applied, the hand is put into a mosquito cage with qualified attack power for 2 minutes to observe whether there are mosquitoes coming to land and suck blood. After that, the test is conducted every 1 hour. As long as one mosquito comes to suck blood, the repellent is judged to be invalid, and the effective protection time (h) of the repellent is recorded. Each time, a control test is performed on the control hand first. Test insects with qualified attack power can continue to be tested. If the test insects have unqualified attack power, qualified test insects need to be replaced for testing. The repellent rate PR calculation formula is: PR = (Nc-Nt) / Nc × 100%, Nc represents the number of mosquito bites on the control hand, and Nt represents the number of mosquito bites on the treatment group.

[0064] Mechanical strength: The mechanical strength of the plant essential oil mosquito repellent sustained-release gel prepared in the examples and comparative examples was tested using a texture analyzer (TA.XTPlus, SMS). The plant essential oil mosquito repellent sustained-release gel prepared in the examples and comparative examples was evenly cut into cylinders with a diameter of 10 mm and a height of 20 mm. A push joint was used to apply force to compress the hydrogel to 60% of its original height at a speed of 1 mm / s.

[0065] The following table shows the performance data of the plant essential oil mosquito repellent slow-release gel prepared in the examples and comparative examples:

[0066]

[0067] By comparing the performance data of the embodiments and comparative examples in the above table, it can be seen that the plant essential oil mosquito repellent sustained-release gel prepared in Examples 1 to 4 has a good sustained-release effect, a good mosquito repellent effect, a high mechanical strength, and a soothing and pleasant smell; by comparing Example 2 with Comparative Examples 1 to 3, it can be seen that Example 2 uses plant essential oil microcapsules, modified graphene oxide, hydroxybutyl chitosan, and hyaluronic acid to prepare the plant essential oil mosquito repellent sustained-release gel. The prepared plant essential oil mosquito repellent sustained-release gel has plant essential oil microcapsules, modified graphene oxide, Hydroxybutyl chitosan and hyaluronic acid act synergistically to form a gel with high cross-linking density, which has better sustained-release effect and higher mechanical strength. Comparison between Example 2 and Comparative Examples 4 to 8 shows that Example 2 uses 20 to 30 parts by mass of peppermint oil, 15 to 25 parts by mass of lime oil, 15 to 25 parts by mass of ylang-ylang oil, 10 to 20 parts by mass of laurel oil, and 15 to 25 parts by mass of ginger oil to compound the compound plant essential oil, and the obtained plant essential oil mosquito repellent sustained-release gel has better sustained-release effect and a more soothing and better smell.

[0068] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A plant essential oil mosquito repellent slow-release gel, characterized in that: The raw material components of the plant essential oil mosquito repellent sustained-release gel include plant essential oil microcapsules, modified graphene oxide, hydroxybutyl chitosan and hyaluronic acid.

2. The plant essential oil mosquito repellent slow-release gel according to claim 1, characterized in that: The plant essential oil microcapsule is obtained by encapsulating the compound plant essential oil with gelatin and gum arabic as shell materials.

3. The plant essential oil mosquito repellent slow-release gel according to claim 2, characterized in that: The compound plant essential oil comprises the following components by weight: 20 to 30 parts by weight of peppermint oil, 15 to 25 parts by weight of litsea cubeba oil, 15 to 25 parts by weight of ylang-ylang oil, 10 to 20 parts by weight of laurel oil, and 15 to 25 parts by weight of ginger oil.

4. The plant essential oil mosquito repellent slow-release gel according to claim 1, characterized in that: The modified graphene oxide is obtained by modifying graphene oxide with dopamine.

5. A method for preparing the plant essential oil mosquito repellent slow-release gel according to any one of claims 1 to 4, characterized in that: The following steps are involved: (1) 0.2-0.6 parts by weight of plant essential oil microcapsules are mixed with 2 parts by weight of PBS buffer, stirred until uniformly dispersed, then 0.1-0.3 parts by weight of hydroxybutyl chitosan is added and stirred until the hydroxybutyl chitosan is dissolved, and then 0.003-0.005 parts by weight of modified graphene oxide is added and stirred and dispersed at 0-4° C. for 25-35 minutes to obtain a modified graphene oxide / hydroxybutyl chitosan mixed solution; (2) At 0-4° C., the modified graphene oxide / hydroxybutyl chitosan mixed solution and the hyaluronic acid solution are mixed in a volume ratio of 1.5-2.5:1 to obtain a plant essential oil mosquito repellent sustained-release gel.

6. The method for preparing the plant essential oil mosquito repellent slow-release gel according to claim 5, characterized in that: The preparation steps of the plant essential oil microcapsules are as follows: gelatin and water are mixed at a mass ratio of 1.5-2.5:97.5-98.5 at 50°C to obtain a gelatin solution; gum arabic powder and water are mixed at a mass ratio of 1.5-2.5:97.5-98.5 at 50°C to obtain a gum arabic solution; the gelatin solution and the gum arabic solution are mixed in equal volumes to obtain a mixed solution; then the compound plant essential oil and the mixed solution are emulsified at a mass ratio of 2:1 using an emulsifying homogenizer at high speed for 2.5-3.5 minutes, then stirred and mixed at 39-41°C and 400-800rpm, the pH is adjusted to 3.4-4.0 with a 10% acetic acid solution, then stirred and reacted for 30 minutes, then cooled to below 10°C, the pH is adjusted to 6 with a 10% sodium bicarbonate solution, 0.5-0.7 parts by mass of transglutaminase is added, and a curing reaction is carried out for 5-7 hours, and then filtered, washed, centrifuged, and dried to obtain the plant essential oil microcapsules.

7. The method for preparing the plant essential oil mosquito repellent slow-release gel according to claim 5, characterized in that: The pH of the PBS buffer is 7.

4.

8. The method for preparing the plant essential oil mosquito repellent slow-release gel according to claim 5, characterized in that: The preparation steps of the modified graphene oxide are as follows: 0.03-0.05 parts by mass of graphene oxide is dispersed in 30-50 parts by mass of 100mM tris(hydroxymethyl)aminomethane hydrochloride buffer solution, and ultrasonicated for 20-40 minutes, then 0.03-0.05 parts by mass of dopamine is added, and ultrasonicated for 20-40 minutes. After the ultrasonication, the mixture is stirred for 23-25 ​​hours, and the supernatant is discarded by centrifugation. The obtained precipitate is repeatedly washed with ethanol and water for 6-8 times, and the modified graphene oxide is obtained after freeze-drying.

9. The method for preparing the plant essential oil mosquito repellent slow-release gel according to claim 5, characterized in that: The preparation steps of the hyaluronic acid solution are as follows: 0.09-0.11 parts by mass of hyaluronic acid are dissolved in a PBS buffer solution with a pH of 7.4 to obtain a 100 mg / mL hyaluronic acid solution.

Images